In February, 1986, an international conference on the surgical treatment of epilepsy was held in Palm Desert, California. By that time, a century of experience involved considerable technological development but relatively few quantitative clinical investigations, resulting in a great diversity of philosophies and practiced approaches; perhaps greater than in any other field of medicine. For the first time, representatives from over 50 epilepsy surgery centers, representing 17 countries, sat down to identify their agreements and disagreements, and to discuss controversies that required resolution. This conference, and the resultant text, essentially defined the field of epilepsy surgery as it existed in 1986. There has subsequently been an explosion of interest in surgical treatment of epilepsy and a tremendous expansion of epilepsy surgery centers worldwide, accompanied by an increase in both basic and clinical research on the subject, application of a number of new technological advances, and several ,ore international conferences. As the safety and efficacy of surgical intervention for medically refractory epilepsy has progressively improved, and the types of patients who might be considered surgical candidates has greatly increased, the number of surgeries performed has by no means kept up with the calculated need. This can be attributed in part to failure to educate referring physicians and third party payers concerning recent advances in the field, and in part to the persistence of both real and perceived controversies. In keeping with the recent NIH Consensus Conference on Surgery for Epilepsy (by at least tenfold), and that more multi-centered quantitative studies are necessary to resolve current differences in approaches and to document therapeutic efficacy, a second Palm Desert international conference is proposed. This conference will follow the same format as the first Palm Desert conference, but will be designed specifically to: 1. define the current state of the field and document progress made over the past 5-6 years; 2. document the increasing agreement that has occurred among workers in epilepsy surgery centers and determine whether this agreement is based on actual data; 3. identify areas of continued controversy, and determine whether these controversies could be resolved by cooperative efforts; 4. generate a plan to disseminate information concerning appropriate approaches for the surgical treatment for epilepsy, and a plan for resolving recognized controversies over the next five to ten years; 5. explore how basic and clinical neuroscientists can best work together to take maximum advantage of unique research opportunities; and 6. publish a second edition of Surgical Treatment of the Epilepsies.